Unitary endoscopic vessel harvesting devices

ABSTRACT

Unitary endoscopic vessel harvesting devices are disclosed. In some embodiments, such devices comprise an elongated body having a proximal end and a distal end, a tip disposed at the distal end of the elongated body; and a cutting unit having a first cutting portion and a second cutting portion, the first cutting portion and the second cutting portion being moveable in a longitudinal direction relative to the elongated body to capture a blood vessel between the first cutting portion and the second cutting portion, and being rotatable relative to one another circumferentially about the tip to cut the captured blood vessel.

RELATED APPLICATIONS

This application is a divisional patent application of U.S. patentapplication Ser. No. 14/190,873, filed Feb. 26, 2014, which claimspriority to and the benefit of U.S. Provisional Application No.61/782,034, filed Mar. 14, 2013 and U.S. Provisional Application No.61/833,814, filed Jun. 11, 2013, each of which is incorporated herein byreference in its entirety.

TECHNICAL FIELD

The presently disclosed embodiments relate to endoscopic cannulas andmethods of their use.

BACKGROUND

Vessel harvesting is a surgical technique that is commonly used inconjunction with coronary artery bypass surgery. During a bypasssurgery, blood is rerouted to bypass blocked arteries to restore andimprove blood flow and oxygen to the heart. The blood may be reroutedusing a bypass graft, where one end of the by-pass graft is attached toa blood source upstream of the blocked area and the other end isattached downstream of the blocked area, creating a “conduit” channel ornew blood flow connection bypassing the blocked area. Commonly, asurgeon will remove or “harvest” healthy blood vessels from another partof the body to create the bypass graft. The success of coronary arterybypass graft surgery may be influenced by the quality of the conduit andhow it is handled or treated during the vessel harvest and preparationsteps prior to grafting.

Vessel harvesting methods involve selecting a vessel, traditionally, thegreat saphenous vein in the leg or the radial artery in the arm to beused as a bypass conduit sealing off and cutting smaller blood vesselsthat branch off the main vessel conduit and harvesting the main conduitfrom the body. This practice does not harm the remaining blood vesselnetwork, which heals and maintains sufficient blood flow to theextremities, allowing the patient to return to normal function withoutnoticeable effects.

Minimally invasive technique for vessel harvesting is known asendoscopic vessel harvesting, a procedure that requires only smallincisions. While the endoscopic vessel harvesting procedure is animprovement over a traditional “open” procedure that required a single,long incision from groin to ankle, the endoscopic procedure is stillcumbersome and difficult. In particular, current endoscopic harvestingsystems require multiple tools, which increases the potential for injuryto the bypass conduit as well as increases the duration of theprocedure. Accordingly, improvements in systems and methods forendoscopic vessel harvesting are still needed.

SUMMARY

Unitary endoscopic vessel harvesting devices are disclosed. In someembodiments, such devices comprise an elongated body having a proximalend and a distal end, a tip disposed at the distal end of the elongatedbody; and a cutting unit having a first cutting portion and a secondcutting portion, the first cutting portion and the second cuttingportion being moveable in a longitudinal direction relative to theelongated body to capture a blood vessel between the first cuttingportion and the second cutting portion, and being rotatable relative toone another circumferentially about the tip to cut the captured bloodvessel.

In some embodiments, a surgical device of the present disclosurecomprise an elongated body having a central axis extending between aproximal end and a distal end and a tip disposed at the distal end ofthe elongated body. In some embodiments, the tip may include an internalapex; an indented external apex at a distal end of the tip, wherein theinternal apex and the external apex are co-linear with the central axisof the elongated body. The surgical device may further include a cuttingunit disposed about the tip and moveable in longitudinal direction alongthe elongated body to capture a blood vessel and to cut the bloodvessel.

In some embodiments, the present disclosure provides a method forharvesting a blood vessel, the method includes a step of advancing acannula having a dissection tip disposed at a distal tip of an elongatedbody along a main vessel to separate the main vessel and its branchvessels from the surrounding tissue. The method further includes a stepof moving a first cutting portion and a second cutting portion in adistal direction from a position proximally of the dissection tip tocapture a blood vessel between the first and second cutting portions androtating at least one of the first cutting portion and the secondcutting portion circumferentially about the tip toward one another tocut the captured blood vessel.

BRIEF DESCRIPTION OF DRAWINGS

The presently disclosed embodiments will be further explained withreference to the attached drawings, wherein like structures are referredto by like numerals throughout the several views. The drawings shown arenot necessarily to scale, with emphasis instead generally being placedupon illustrating the principles of the presently disclosed embodiments.

FIG. 1A illustrates a side view of an embodiment of an endoscopiccannula of the present disclosure.

FIG. 1B and FIG. 1C illustrate an embodiment of a dissection tip of thepresent disclosure having an indent at the distal tip.

FIG. 2A, FIG. 2B and FIG. 2C illustrate a dissection procedure using anendoscopic cannula of the present disclosure.

FIG. 3A, FIG. 3B and FIG. 3C illustrate an embodiment of a cutting unitof an endoscopic cannula of the present disclosure.

FIG. 4A, FIG. 4B, FIG. 4C, and FIG. 4D illustrate an embodiment of acutting unit of an endoscopic cannula of the present disclosure.

FIG. 5 illustrates an embodiment of a control handle suitable for usewith an endoscopic cannula of the present disclosure.

FIG. 6A, FIG. 6B, FIG. 6C, FIG. 6D, FIG. 6E and FIG. 6F illustrate anembodiment of an endoscopic cannula of the present disclosure inoperation being controlled by the control handle of FIG. 5.

FIG. 7A and FIG. 7B illustrate an embodiment of a cutting unit of anendoscopic cannula of the present disclosure.

FIG. 8 illustrates an embodiment of a cutting unit of an endoscopiccannula of the present disclosure.

FIG. 9A, FIG. 9B and FIG. 9C illustrate an embodiment of a cutting unitof an endoscopic cannula of the present disclosure.

FIG. 10A and FIG. 10B illustrate an embodiment of a cutting unit of anendoscopic cannula of the present disclosure.

While the above-identified drawings set forth presently disclosedembodiments, other embodiments are also contemplated, as noted in thediscussion. This disclosure presents illustrative embodiments by way ofrepresentation and not limitation. Numerous other modifications andembodiments can be devised by those skilled in the art which fall withinthe scope and spirit of the principles of the presently disclosedembodiments.

DETAILED DESCRIPTION

The present disclosure provides a unitary device for endoscopic vesselharvesting. Present systems for endoscopic vessel harvesting containmultiple components. Typically, an endoscopic dissection device is usedto isolate the main vessel from the surrounding connective tissue bydissecting the main vessel from surrounding connective tissue. Anendoscopic cannula is then used to introduce yet another device, anendoscopic tributary sealing instrument, to seal and sever sidebranches. Once the side branches are sealed, yet another device is usedto harvest a section of the main vessel to be used as a bypass graft.The unitary devices of the present disclosure combine the dissectionfunction, the tributary sealing and severing function, and, optionally,main vessel sealing and severing function, which can result in decreasedvessel manipulation and improvement in ease of the procedure. Thedevices of the present disclosure may also be used to extract the sealedand severed main vessel from the patient.

Decreased vessel manipulation may decrease the potential for injury tothe graft. Repeated vessel contact with multiple passes of harvestinginstrumentation increases potential vessel injury. A unitary device suchas the device of the present disclosure may dissect, i.e., separate themain vessel, from surrounding tissue, cauterize and transect thetributaries and the main vessel as the device is advanced, and thevessel may be harvested with a single passage of the device, rather thanmultiple device insertions and retractions. Such a device with adecreased diameter may be used for dissection as well as tributaryligation; graft trauma should be decreased. The relative smallerdiameter of the present device can also facilitate harvesting of moretortuous vessels; for example, the internal mammary artery.

Referring to FIG. 1A, an endoscopic cannula 100 of the presentdisclosure includes an elongated body 102 having a proximal end 104 anda distal end 106, terminating with a dissection tip 120. The cannula 100further includes an cutting unit 150 disposed about the distal end 106for sealing and cutting a blood vessel and a control handle 160 forcontrolling the cutting unit 150.

In some embodiments, the elongated body 102 is configured for passingextravascularly through an entry incision to a vessel harvesting site.To aid in navigating the elongated body 102 to a site of harvesting, theelongated body 102 may be sufficiently rigid axially along its length.To provide the elongated body 102 with such characteristic, in anembodiment, the elongated body 102 may be made from a biocompatiblematerial, such as, plastic material, elastomeric material, metallicmaterial, shape memory material, composite material or any othermaterials that has the desired characteristics. To the extent desired,the elongated body 102 may be provided with some flexibility to moveradially or laterally from side to side depending on the application.

In some embodiments, the elongated body 102 of the cannula 100 may besolid. In other embodiments, the endoscopic cannula 100 may include oneor more lumen with lumena that accommodate advancing instruments ormaterials therethrough. In some embodiments, the endoscopic cannula 100may include an endoscopic lumen 103 through which an endoscope 116 maybe advanced for visualizing procedures performed using the cannula 100.The endoscopic cannula 100 may include an adapter 114 at the proximalend 104 for advancing the endoscope 116 into the endoscopic cannula 100.Additional lumens of the cannula 100 are described below.

In some embodiments, the endoscopic cannula 100 may include a dissectiontip 120 disposed at or about the distal end 106 of the endoscopiccannula 100. The viewing tip of the endoscope may be positioned insidethe dissection tip 120. In some embodiments, the dissection tip 120 mayinclude an inner cavity in fluid communication with the endoscopic lumen103 to enable the endoscope 116 to be advanced into the dissection tip120. In some embodiments, a chip-on-a-tip type of an endoscope may beintegrated inside the dissection tip 120. The tip 120 may also betransparent to allow for endoscopic viewing through the tip 120 of theprocedures performed using the cannula 100. The dissection tip 120 insome embodiments, may be provided with any shape as long as itfacilitates endoscopic viewing therethrough, and allows for necessarycontrol during tissue dissecting, i.e. separation. In some embodiments,the dissection tip may be generally conical.

In some embodiments, the dissection tip 120 may include a generally flatshoulder 122, and a tapered section 124 which terminates in blunt end126 for atraumatic separation of a vessel segment, being harvested fromsurrounding tissue, while minimizing or preventing tearing or puncturingof nearby vessels or tissue as the endoscopic cannula 100 is navigatedalong the vessel segment. Although illustrated as being blunt, it shouldof course be understood that, to the extent desired, the end 126 of thedissection tip 120 may be made relatively pointed to enhance advancementof the cannula 100.

In reference to FIG. 1B and FIG. 1C, in some embodiments, the dissectiontip 120 may be cone shaped, and may be shaped at its distal end in amanner so as to minimize the negative effects of visual distortion orblinding at the center of the endoscopic view field when viewing throughan endoscope inserted into the cannula 100, with a light source andcamera system. Internal surface 121 of the dissection tip 120 may betapered, with a relatively constant slope toward the distal end 126 ofthe dissection tip 120, terminating at an internal apex 123, which maybe a sharp point, as shown in FIG. 1C. External surface 125 of thedissection tip 120 may also be tapered with a constant slope toward thedistal end 126 of the dissection tip 120; however, at the distal end126, a relatively rounded, blunt end may be formed to minimize tissuedamage during dissection. As illustrated, at the distal end, theexternal surface 125 of the dissection tip 120 may be folded back onitself in a proximal direction to then terminate at an external apex127, maintaining the blunt exterior surface and forming an indent 129 inthe distal end of the dissection tip 120. Both the internal apex 123 andthe external apex 127 may be collinear with the central longitudinalaxis of the cannula 100 and, thus, in some embodiments, the endoscope116. In other words, the centers of the internal apex 123 and theexternal apex 127 are located on the central longitudinal axis of thecannula 100. By providing an apex on each of the internal surface 121and the external surface 125 of the dissection tip 120 that are alsocollinear with the axis of the endoscope 116, those surfacesperpendicular to the light path (which is parallel to the endoscopeaxis) may be eliminated, which then may eliminate light refraction fromthe perpendicular surface back into the camera and, thus, may minimizeor eliminate the visual distortion or blinding when viewing through theendoscope 116 with a light source and camera system.

To reduce likelihood of trauma during the dissection process, in someembodiments, the dissection tip 120 may be radially pliable, flexible ordeformable so that the dissection tip may deflect slightly underexertion of force applied to the dissection tip 120. In someembodiments, the dissection tip 120 is radially compressible so that thewalls of the dissection tip 120 can deform under exertion of forcenormal to the tip surface. To that end, the dissection tip 120 may beformed from thin wall plastic material to enable the dissection tip toflex under load. Suitable materials include, but are not limited to,polycarbonate, polyethylene terephthalate glycol-modified (PETG),polyethylene terephthalate (PET) and other materials that provide enoughoptical clarity while allowing the dissection tip to flex under load. Atthe same time, the dissection tip 120 may be provided with sufficientcolumn strength in axial or longitudinal direction to allow dissectionof the vessel from the surrounding connective tissue.

In reference to FIGS. 2A-2C, blood vessels used in bypass grafting (e.g.greater saphenous vein or radial artery), lie in the subcutaneous space,beneath the surface of the skin. The vessel 200 is composed of a maintrunk 210, and branch vessels 220 that emanate from the vessel trunk210, as shown in FIG. 2A. The vessel 200 and its branches 210 areencased in subcutaneous fatty connective tissue 230, and need to bedissected free of the surrounding fatty connective tissue 230 before themain vessel 200 may be harvested. The subcutaneous fat 230 is softerthan skin, muscle, fascia or other connective tissues. Although adherentto the vessel 200, the fatty connective tissue 230 forms an interface240 with the vessel 200 that may be cleanly dissected; that is, there isa natural dissection plane between the outer layer of the vessel 200(the adventitia), and the surrounding subcutaneous fat 230.

FIG. 2B illustrates dissection of the main trunk 210 of the vessel 200with the dissection tip 120 along the natural dissection plane, with thedissection tip 120 advanced along the adventitial surface of the vessel200. Isolation of the vessel 200 from surrounding fatty connectivetissue 230 along this plane, typically, does not require high dissectionforces. In some embodiments, the dissection tip may 120 be provided withsufficient column strength to dissect the vessel 200 from thesurrounding fatty connective tissue 230 along the natural dissectionplane between them.

On the other hand, as is illustrated in FIG. 2C, as the dissection tip120 approaches a branch vessel 220, the dissection tip 120 may catch thebranch vessel 220 at a junction 250 between the branch vessel 220 andthe main vessel 200. Application of excessive force with the dissectiontip 220 may avulse the branch vessel and sever it from the trunk vessel,or may otherwise cause damage to the main vessel 200. To that end, insome embodiments, the dissection tip 120 is provided with sufficientcolumn strength to dissect the vessel 200 from the surrounding tissue230 along the natural dissection plane between them, while beingsufficiently pliable to deform or deflect from the branch vessel 220with the application of increased force, to decrease the potential oftrauma to the graft vessel during dissection around branch vessels. Itshould of course be understood that the rigidity of the dissection tip120 may be varied from fully flexible to semi-rigid to rigid, inaccordance with requirements of the procedure.

The cannula 100 may further include one or more end-effectors forcauterizing or sealing and cutting a blood vessel, either a branchvessel or the main vessel.

In reference to FIG. 3A, in some embodiments, the cutting unit 150 ofthe cannula 100 may include a first cutting member 302 and a secondcutting member 304, each having a cutting portion 310, 312 extendingfrom their respective distal ends.

The first cutting member 302 and the second cutting member 304 may bemoveable in a longitudinal direction relative to the elongated body 102of the cannula 100. In this manner, the cutting portions 310, 312 may bemoved from an initial, retracted position during the dissection, inwhich the cutting portions 310, 312 are retracted substantiallyproximally of the dissection tip 120 not to interfere with thedissection, to an operational or extended position for sealing andcutting, in which the cutting portions 310, 312 may be advanced distallyfor the user to see the cutting portions and to provide enough capturelength for the vessel. In some embodiments, the cutting portions 310,312 may at least partially extend beyond the dissection tip 120 tocapture a blood vessel the cutting portions 310, 312. In addition, insome embodiments, the first cutting member 302 and the second cuttingmember 304 may be rotatable relative to one another. In this manner, thecutting portions 310, 312 may be moved from an open position when thecutting portions 310, 312 are apart or spaced away from one another tocapture a blood vessel therebetween, as shown in FIG. 3B, to a closedposition when the cutting portions 310, 312 are brought towards oneanother around the dissection tip 120 to seal and cut the blood vessel,as shown in FIG. 3C. In some embodiments, the first cutting member 302and the second cutting member 304 are configured so both cuttingportions 310, 312 can be rotated circumferentially about the dissectiontip 120 toward one another in both clockwise and counterclockwisedirection depending on the location of the blood vessel to be capturedbetween the cutting portions 310, 312. Such bi-directional,circumferential movement of the cutting portions 310, 312 may allow theuser to operate on blood vessels on all sides of the cannula 100 to savetime and reduce cannula manipulation during the procedure as the userdoes not need to be concerned about the orientation and position of thecannula 100 in relation to the blood vessel. In addition, it may reducethe potential for the cutting portions to twist the side branches,thereby exerting traction on the blood vessel and consequent damage tothe graft. The bi-directional movement may also be more-intuative to theuser and eliminates the need to remember which side is the active sidefor cautery and cutting. In other embodiments, one of the cuttingportions 310, 312 may be stationary and the other one may rotate in bothclockwise and counterclockwise toward the stationary cutting portion foreasier manipulation and visualization of the cutting portions 310, 312.Of course, the stationary cutting portion may also be moved to a desiredorientation by moving the cannula 100.

The cutting portions of the cutting members 302, 304 may generally beelliptical or blade-like with a rounded distal tip, but any other shapethat enables the cutting and sealing of a blood vessel may also be used.To facilitate sealing of the blood vessel, one or both of the cuttingportions 310, 312 may be energized, when needed, using various sourcesof energy, including, but not limited to, resistive heating, ultrasoundheating, and bipolar or monopolar RF energy. In some embodiments, theelectrodes can be controlled independently of one another. In someembodiments, the cutting portions 310, 312 may be made from a materialsuch as metal that would enable the cutting portions 310, 312 themselvesto be energized. Additionally or alternatively, energizing elements,such as metal wires, may be disposed on the cutting portions 310, 312.When energized, the energizing elements may be brought in contact withthe blood vessel by the cutting portions 310, 312 to seal the bloodvessel. In some embodiments, one or both of the cutting members 310, 312may include protrusions for use as spot cautery. In some embodiments,one or both of the cutting members 310, 312 may have a sharpened, thinedge for concentrated application of energy to the blood vessel. Suchconcentrated energy application may require less energy to be applied tothe side branch, thereby minimizing extension of cauterizing energy fromthe side branch towards the main trunk of the blood vessel, and thuseliminating potential trauma to the blood vessel.

To facilitate cutting of the blood vessel subsequent to sealing of theblood vessel, in some embodiments, one of the opposing edges 318, 320 ofthe cutting portions 310, 312 between which cutting occurs may have aleveled face while the other one may be a sharpened, thin or pointed sothat the tissue is not cut in a scissor-like motion but with a thin edgeagainst a flat surface. To that end, in some embodiments, both edges ofthe cutting members 310 may be sharpened edges, while both edges of thecutting portion 312 may be flat, or vise versa. Alternatively, thecutting portions 310, 312 may have one sharp edge or blade edge and oneflat edge with the sharp edge of one cutting portion facing the flatedge of the other cutting portion. It should be noted that in someembodiments, the blood vessel may be both sealed and cut using energy,as described above. It should of course be understood that, in someembodiments, the opposing edges the opposing edges 318, 320 of thecutting portions 310, 312 may both be sharpened so the tissue is cut ina scissor-like manner.

As shown in FIG. 3B and FIG. 3C, in some embodiments, the cuttingmembers 302, 304 may be substantially u-shaped and disposed in the sameplane relative to the cannula body 102. In some embodiments, the cuttingmembers 302, 304 may include respective cutouts and fingers 314, 316along the edges to enable circumferential movement of the cuttingmembers 302, 304 relative to one another.

In reference to FIG. 4A and FIG. 4B, in some embodiments, the cuttingmembers 302, 304 may be substantially tubular and be disposed indifferent planes of the cannula body 102. As shown in FIG. 4A, in someembodiments, the cutting member 304 may be concentrically disposedinside within the cutting member 302. Referring to FIG. 4B, in someembodiments, the elongated body 102 of the cannula 100 may beconstructed of a series of coaxial tubes, both metal and plastic, thatmay act as the structural main shaft, the electrical conductive andinsulative paths, and the end-effectors, i.e. cutting portions 310, 312.In some embodiments, there may be three plastic sheaths acting aselectrical insulators and mechanical bearing surfaces sandwiched inbetween two metal conductive tubes for the entire length of the device.The innermost layer may be the inner sheath 402 (plastic) defining aninternal lumen 403. The inner sheath 402 may be followed outwardly bythe inner electrode tube 404 (metal), middle sheath 406 (plastic), outerelectrode tube 408 (metal) and outer sheath 410 (plastic), and finally ashrink jacket 412. In some embodiments, instead of three plasticsheaths, the electrical insulation may be provided using non-conductivecoatings or similar means. For example, in some embodiments, theelectrodes 404, 408 may be coated with polyvinyldyne flouride (PVDF),but other non-conductive coating may also be used.

The inner electrode tube 404 and the outer electrode tube 408 may beused to form the first cutting member 302 and the second cutting member304, with the cutting portions 310, 312 being formed at the distal endsof the inner electrode tube 404 and the outer electrode tube 408. Toenable the cutting portions 310, 312 to capture, seal and cut bloodvessels, the inner electrode tube 404 and the outer electrode tube 408may be slidable in the longitudinal direction relative to the cannula100 and rotatable relative to one another. Further, because the cuttingportions 310, 312 are formed from the inner electrode tube 404 and theouter electrode tube 408, the cutting portions 310, 312 can be easilyenergized through the inner electrode 404 and the outer electrode 408.In some embodiments, the cutting portion formed from the inner electrodetube 404 (i.e. inner cutting portion 411) may be bent out of the planeof the inner electrode 404 to enable it to rotate along the same axisand be co-radial with the cutting portion formed in the outer electrode408 (i.e. outer cutting portion 413). In some embodiments, the innercutting portion 411 may have a flat face 416 on either side of the innercutting portion, while the outer cutting portion 413 may have asharpened or blade edge 418 on both sides, or vice versa. In otherembodiments, as described above, each cutting portion 411, 413 may haveone sharpened edge and one flat edge, with the flat edge of one cuttingportion facing the sharpened edge of the other cutting portion.

In reference to FIG. 4C, in some embodiments, the dissection tip 120 maybe connected to the inner sheath 402 to enable the advancement of theendoscope 116 into the dissection tip though the internal lumen 403. Asleeve 414, or transition, may be used to protect tissue from damageduring dissection by smoothing the geometry between the dissection tip120 and the cannula body 102. The distal end of the sleeve 414 may beleft unattached to the dissection tip 120 to allow the cutting portions312, 314 to be advanced distally through the sleeve 414, as shown inFIG. 4D. In some embodiments, the sleeve 414 may be made of a flexiblematerial so during dissection the sleeve 414 would comply with thedissection tip creating a smooth transition and also a tight seal toprevent tissue or bodily fluids from entering the cannula 100. On theother hand, a flexible sleeve would be able to deflect and expand toallow the cutting portions 312, 314 to be advanced out distally thoughthe sleeve 414. In some embodiments, the surface of the sleeve may becoated with a lubricious substance to make the extension of the cuttingportions 312, 314 through the sleeve 414 easier and smoother bydecreasing friction between the cutting portions 312, 314 and the sleeve414. The thin-walled shrink tube 412 may be placed over the outersurface of the cannula body for aesthetic purposes and to assist insecuring the transition.

FIG. 5 illustrates an embodiment of the control handle 160 forcontrolling the cutting members 310, 312. In some embodiments, thecontrol handle 160 may include a translation control 502 for advancingand retracting the cutting members 310, 312. The control handle furtherincludes a rotation control 504 for rotating the cutting members withrespect to one another. Finally, the control handle 160 includes anenergy control 506 for supplying energy (such as bipolar RF energy) tothe cutting portions 310, 312. The adapter 114 may be located at theproximal end of the control handle 500 for advancing the endoscope 116into the endoscopic cannula 100.

In operation, an initial incision may be made in conventional manner toexpose the target vessel (e.g., the saphenous vein). The cannula 100 maybe inserted into the incision and guided to the target vessel. In someembodiments, the cannula 100 may include a smooth tubular sheath aroundthe elongated body 102 for sealing the cannula 102 within the portthrough which the cannula 102 is introduced into the patient. Thecannula 100 may then be advanced substantially along the target vesselto dissect the target vessel from the surrounding tissue. In someembodiments, the cannula 100 may be introduced through a sealable portused to seal the incision to allow insufflation of the space created bythe dissection of the target vessel from surrounding tissues.

As the cannula 100 is being advanced, the cutting portions 310, 312 ofthe cutting elements 302, 304 may be kept in a retracted position so notto interfere with tissue dissection until a branch vessel isencountered. At that point, the cutting portions 310, 312 may beadvanced beyond the dissection tip 120, as described above, to capture,seal and cut the branch vessel.

In reference to FIGS. 6A-6F, in some embodiments using the controlhandle 160, the cutting portions 310, 312 may be moved from a retractedposition, as shown in FIGS. 6A-6B, in the distal direction beyond thedissection tip 120 by advancing the translational control 504 on thehandle to its distal position, as shown in FIGS. 6C-6D. The cuttingportions 310, 312 may be advanced out together and enter into the fieldof view of the endoscope in the dissection tip 120. Next, the cuttingportions 310, 312 may be rotated with respect to one another using therotation control 504, as shown in FIGS. 6E-6F, for sealing and cuttingthe branch vessel. The cutting portions 310, 312 may be rotated aroundthe dissection tip 120 in a circular arc motion. The endoscopic cannula100 may be positioned such that the target branch vessel may lay acrossone of the cutting portions 310, 312, regardless of orientation of thebranch vessel in relation to the main blood vessel to be harvested. Theendoscopic cannula 100 may be designed such that the user can place theendoscopic cannula 100 and the cutting portions 310, 312 as far awayfrom the target main vessel as possible to avoid injury to the mainvessel. Once in position, the user may rotate one of the cuttingportions 310, 312 toward the other one until the branch vessel iscaptured. If positioned properly, the rotation is preferably always awayfrom the main vessel, thus increasing and further maximizing thepotential negative effects of lateral thermal spread. Next, when thebranch vessel is positioned in between the cutting portions 310, 312,the user may depresses the energy control 508 button to transfer theenergy into the tributary to seal the vessel. After sealing is completeand the energy control button 508 is released, the user may continue toadvance the rotation control 504 until the cutting portions 310, 312transect the branch vessel. The user may then retract the cuttingportions 312, 314 with the translation control 502 and advance thedevice to the next branch vessel until all tributaries have beensuccessfully ligated and transected.

After the branch vessel has been hemostatically severed, the cannula 100may be advanced forward until the next branch vessel is encountered, atwhich point the branch vessel may be sealed and severed using thecutting unit 300. Once all branch vessels along a desired length of thetarget vessel have been sealed and severed, the cannula 100 may be usedto seal and cut the target vessel according to procedure similar to theprocedure used to cut and seal the branch vessels. Alternatively, thecannula 100 may be withdrawn, and another surgical device may be used toseal and cut the main vessel.

In some embodiments, the cannula 100 of the present disclosure may allowvessel sealing and cutting to be performed in a small cavity.Accordingly, when using the cannula 100 of the present disclosure theremay not be a need to maintain the perivascular cavity in an expandedstate and thus the procedure may be performed without gas insufflationof the perivascular cavity. In operation, the transparent dissection tip120 can deflect a vessel to one side, so that the members of the cuttingunit can capture the vessel, while maintaining visualization of allcomponents in a collapsed tissue tunnel. Vessel harvesting in a small orcollapsed cavity may be useful in anatomic situations characterized byvessel tortuosity, such as the internal mammary artery and vein.Harvesting without gas insufflation may also be beneficial to the graft.The carbonic acid environment of a cavity maintained by carbon dioxidegas insufflation may be detrimental to the graft vessel. A lower pHatmosphere surrounding the vessel may alter the cellular viability ofthe graft, potentially leading to early graft failure. Positive pressureproduced by gas insufflation may also collapse the vessel, causinghemostasis, and may increase the potential for intraluminal clotformation. Presence of intraluminal clot may cause graft thrombosis andearly graft failure.

In reference to FIG. 7A and FIG. 7B, the cutting unit 150 may include afirst member 702 and a second member 704. In some embodiments, the firstmember 702 and second member 704 may be translatable relative to thedissection tip 120 from a proximal position, during the dissection, to amore distal position to capture, seal and cut the blood vessel.Moreover, the first member 702 and second member 704 may also bemoveable relative to one another so the first member 702 and secondmember 704 can be space away from one another capture a blood vesseltherebetween and then may be compressed against one another to seal andcut the blood vessel. To permit such movements of the first member 702and second member 704, in some embodiments, the first member 702 andsecond member 704 may be mounted on one or more actuating rods foradvancing and retracting. It should, of course, be understood that othermechanisms for translating the first member 702 and second member 704relative to the dissection tip 120 and one another may be employed.

The first member 702 may include four circumferentially-disposedproximal electrode segments 706 for bipolar RF cutting. The proximalelectrode segments may be connected by 0.020″ conductor. The secondmember 704 may include two circumferentially-disposed distal electrodesegments 708 for bipolar RF cutting. The distal electrode segments maybe connected by 0.020″ conductor. In addition, the second member 704 mayinclude two segments 710 for resistive heat cautery 706 disposeddistally of the distal electrode segments, and a distal ring electrode712 for monopolar cautery. The actuating rods may be employed toenergize the electrodes 706-712.

In reference to FIG. 8, in some embodiments, the cutting unit 150 mayinclude a first member 802 and a second member 804. The first member 802and the second member 804 are translatable relative to the dissectiontip and one another, as described above. In this embodiment of thecutting unit 150, the three electrodes 708, 710, and 712 of the secondmember 704 (see FIGS. 7A and 7B) are combined into one solid ring. Inbipolar mode the only one side of the ring may work with active proximalsegment. In monopolar mode, the entire ring may work with outsidereturned electrode. In some embodiments, two large cross-sectionconductors may also replace four electrode segments, two for RF cuttingand two for resistive heat cautery, which may increase rigidity of thedistal structure.

Moreover, the four electrodes 706 of the first member 702 can also becombined into two hemispheric electrodes 806, which can be individuallycontrolled. In this manner, only two larger cross-section conductors 808may be used instead of four small ones, as in the cutting unitillustrated in FIGS. 7A and 7B. Rigidity of the proximal structure mayalso increase by combining the four electrodes into two.

In reference to FIG. 9A, in some embodiments, the cutting unit 150 mayinclude a first member 902 having a proximal electrode 916 for bipolarRF cutting. The cutting unit 150 may also include a second member 904having a distal electrode 918 for bipolar RF cutting. The cutting unit150 may further include an electrode 914 for monopolar spot cauterydisposed over the dissection tip 120. In some embodiments, the firstmember 902 and the second member 904 may be made of a conductivematerial, with optional coating, and the electrodes 914, 916, 918 may beenergized through the cutting member 902, 904.

In reference to FIG. 9B and FIG. 9C, in some embodiments, the firstmember 902 and the second member 904 may be tubular, with the firstmember 902 slidably disposed relative to the second member 904 to enablethe first member 902 and the second member 904 to be biased relative toone another in a longitudinal direction. In some embodiments, the firstmember 902 and the second member 904 may be move in a distal directionbetween an inactive position proximal of the dissection tip 120, asshown in FIG. 9A, and an active position in the field of view of theendoscope, as shown in FIG. 9B and FIG. 9C, for capturing, cutting andsealing the blood vessel.

The second member 904 may include one or more hooks 910, 912 at a distalregion of the second member 904. The hook 910, 912 may be configured tocapture the branch vessel, as shown in FIG. 9B. In some embodiments, thesecond member 904 may include two hooks 910 and 912, in a spacedrelation to one another, so that the branch vessel may be contacted, ata minimum, by one of the hooks.

In operation, the cannula 100 may be advanced to a vessel with the firstmember 902 and the second member 904 of the cutting unit 150 positionedproximally to the dissection tip 120. As the vessel is encountered, asshown in FIG. 9B, first, the second member 904 may be extended in thedistal direction to capture the branch vessel by the hook of the secondmember 904. Spot cautery may also be performed in this position, asdesired, by a spot cautery electrode 914. Next, the first member 902 maybe advanced to pinch the branch vessel between the electrodes 916, 918of the first member 902 and the second member 904, and the RF currentmay be turned on for sealing and cutting the branch vessel captured inthe cutting unit 150.

FIG. 10A and FIG. 10B illustrate yet another embodiment of the cuttingunit 150 having a first member 1002 and a second member 1004. Incomparison to the embodiment of the cutting unit shown in FIGS. 9A-9C,the second member 1004 may include only a single hook 1010 on one sideof the second member 1004, as compared to two hooks 910, 912 on thesecond member 904. Removing one of hooks may improve visualization ofthe procedure by the endoscope 116 disposed within the cannula 100.Otherwise, the structure and operations of this embodiment of thecutting unit 150 may similar to those of the embodiment of the cuttingunit 150 disclosed in FIGS. 9A-9C.

It should be noted while preferred types of energy for variouselectrodes are indicated in the present disclosure, all electrodes canbe energized using various sources of energy, including, but not limitedto, resistive heating, ultrasound heating, and bipolar or monopolar RFenergy. In some embodiments, the electrodes can be controlledindependently of one another. It should also be noted that, whenappropriate, the electrodes may be insulated with an insulating coatingor insulating sheath.

All patents, patent applications, and published references cited hereinare hereby incorporated by reference in their entirety. It should beemphasized that the above-described embodiments of the presentdisclosure are merely possible examples of implementations, merely setforth for a clear understanding of the principles of the disclosure.Many variations and modifications may be made to the above-describedembodiment(s) without departing substantially from the spirit andprinciples of the disclosure. It will be appreciated that several of theabove-disclosed and other features and functions, or alternativesthereof, may be desirably combined into many other different systems orapplications. All such modifications and variations are intended to beincluded herein within the scope of this disclosure, as fall within thescope of the appended claims.

What is claimed is:
 1. A method for harvesting a blood vesselcomprising: advancing a cannula having a dissection tip disposed at adistal tip of an elongated body along the blood vessel to separate theblood vessel and its branch vessels from surrounding tissue, thedissection tip having an inner cavity terminating at an internal apexand an indented external apex at a distal end of the tip, wherein theinternal apex and the indented external apex are co-linear with acentral axis of the elongated body; moving a first cutting portion and asecond cutting portion in a distal direction from a position proximal ofthe dissection tip to capture the blood vessel between the first andsecond cutting portions; and rotating at least one of the first cuttingportion or the second cutting portion circumferentially about thedissection tip toward one another to cut the captured blood vessel. 2.The method of claim 1 wherein, in the step of moving, the first cuttingportion and the second cutting porting are moved from the positionproximally of the dissection tip to a position over the dissection tip.3. The method of claim 1 further comprising sealing the blood vesselwith a first radio frequency (RF) electrode supported by the firstcutting portion and a second RF electrode supported by the secondcutting portion.
 4. The method of claim 1 wherein, in the step ofrotating, the first cutting portion is stationary and the second cuttingportion is bi-directionally rotatable about the dissection tip.
 5. Themethod of claim 1 wherein, in the step of rotating, the first cuttingportion is stationary and the second cutting portion is rotatable aboutthe dissection tip toward the first cutting portion.
 6. The method ofclaim 1 wherein, in the step of rotating, the first cutting portion hasa sharpened edge and the second cutting portion is flat.
 7. A method forharvesting a blood vessel comprising: advancing a cannula having adissection tip disposed at a distal tip of an elongated body along ablood vessel to separate the blood vessel and its branch vessels fromsurrounding tissue; moving a first cutting portion and a second cuttingportion in a distal direction from a position proximal of the dissectiontip to a position over the dissection tip to capture a blood vesselbetween the first and second cutting portions; and rotating at least oneof the first cutting portion or the second cutting portioncircumferentially about the dissection tip toward one another to cut thecaptured blood vessel, wherein the first cutting portion has a sharpenededge and an edge of the second cutting portion facing the sharpened edgeof the first cutting portion is flat.
 8. The method of claim 7 wherein,in the step of advancing, the dissection tip includes an inner cavityterminating at an internal apex and an indented external apex at adistal end of the dissection tip, wherein the internal apex and theindented external apex are co-linear with a central axis of theelongated body.
 9. The method of claim 7 further comprising sealing theblood vessel with a first RF electrode supported by the first cuttingportion and a second RF electrode supported by the second cuttingportion.
 10. The method of claim 7 wherein, in the step of rotating, thefirst cutting portion is stationary and the second cutting portion isbi-directionally rotatable about the dissection tip.
 11. The method ofclaim 7 wherein, in the step of rotating, the first cutting portion isstationary and the second cutting portion is rotatable about thedissection tip toward the first cutting portion.
 12. A method forharvesting a blood vessel comprising: advancing a cannula having adissection tip disposed at a distal tip of an elongated body along ablood vessel to separate the blood vessel and its branch vessels fromsurrounding tissue; moving a first cutting portion and a second cuttingportion in a distal direction from a position proximal of the dissectiontip to a position over the dissection tip to capture a blood vesselbetween the first and second cutting portions, wherein at least one ofthe first cutting portion or the second cutting portion has a sharpenededge; and rotating at least one of the first cutting portion or thesecond cutting portion circumferentially about the dissection tip towardone another to cut the captured blood vessel, wherein one of the firstcutting portion or the second cutting portion remains stationary as theother of the first cutting portion or the second cutting portion rotatescircumferentially about the dissection tip.
 13. The method of claim 12wherein, in the step of advancing, the dissection tip includes an innercavity terminating at an internal apex and an indented external apex ata distal end of the dissection tip, wherein the internal apex and theindented external apex are co-linear with a central axis of theelongated body.
 14. The method of claim 12 further comprising sealingthe blood vessel with a first RF electrode supported by the firstcutting portion and a second RF electrode supported by the secondcutting portion.
 15. The method of claim 12 wherein, in the step ofrotating, the first cutting portion has the sharpened edge and isstationary and the second cutting portion is bi-directionally rotatableabout the dissection tip.
 16. The method of claim 12 wherein, in thestep of rotating, the first cutting portion has the sharpened edge andis stationary and the second cutting portion is rotatable about thedissection tip toward the first cutting portion.
 17. The method of claim12 wherein, an edge of the second cutting portion is flat.